Issue:
While driving, Jeep shut down. Wouldn't turn over, no spark.


Things I've replaced so far:
-Crankshaft Sensor
-Distributor Cap
-Rotor
-Coil Pack
-Replaced Blown F21 fuse



Managed to get it to start and drive, then it started blowing the F21 fuse. Before it blew the fuse, it ran like it was missing. Now it's at the point where as soon as I start it, it blows the F21 fuse. Checked the wiring for the O2 Sensors and couldn't find any issues- all looks good. Disconnected each of the O2 sensors, one at a time and still blew the fuse when turned to ignition position. Disconnected both O2 sensors and it started right up. Put it into reverse and the fuse blew again. What the fudge!

Any ideas????????

 

Did putting it into reverse make the engine shift? (move) Maybe a coincidence...besides the 02 wires there are a bunch more to the tranny. Just a thought.

 

I'm sure that you know this. But, When ever a fuse keeps blowing it means you have a short in the that system. Your going to have to trace out the wire related to that fuse and it has the plastic cover on the wire harness you will have to pull that back and make sure that none of the wires melted together.

 

Examine the wiring harness loom where it exits the fuel injector wiring manifold and the wiring where it exits the front of the fuel injector wiring manifold for chafing through the loom and to the wiring within.

There have been several accounts of chafing in these areas. Where it exits the back of the manifold chafing has occurred at the end of the fuel rail and at the front of the manifold where the upstream O2S wiring passes over the intake manifold.

In that when you are in gear (reverse in this case) there may be enough engine movement to short out the upstram O2S heater power wire to the fuel rail or the intake manifold, even with the O2S' disconnected.

I take it you have a 2000/2001 XJ by your statement that you changed the Coil Rail. If so, the image of the PDC is not for a 2000/2001 XJ.

Below is the proper image.

 

Hey did this ever get fixed? I am having this exact issue.